1. Field of the Invention
The present invention relates to an external operation detection structure body applicable to various device control panels such as those of audio and navigation systems, and especially to an external operation detection structure body provided with a sealing structure for preventing water or the like from entering the interior.
2. Description of the Related Art
Conventionally, devices such as automobile audio, navigation and air conditioning systems are equipped with an externally operable input unit (interface) for turning on and off the operation and adjusting the volume and temperature. Especially in recent years, as such input unit, touch panels using a manually operated external detection sensor have been considered for use instead of rotating type or mechanical contact type operation switches.
The external operation detection structure body such as a touch panel is generally provided with an aperture window for operation on the sensor casing, where an external operation detection sensor is arranged at the formation zone of the aperture window. The aperture window is closed with a sheet-like interface member covering the surface of the detection sensor, and the external manual operation can be detected via the interface member.
By the way, since such touch panel is provided with an aperture window of the sensor casing, there is a risk of water and dust getting into the sensor casing via the aperture window. Once water or dust gets into the interior of the sensor casing, it can cause failures in the detection sensor or the like arranged at the formation zone of the aperture window.
Hence, conventional touch panels with a conventional structure adopt a sealing structure wherein the periphery of the aperture window of the sensor casing is sealed with a sealing member all the way around as shown in Japanese Patent Nos. 3347009 and 3818046.
However, such sealing structure requires preparation of a separate sealing member to be installed between the sensor casing and the touch panel, which increases the number of parts and makes the assembly work more cumbersome. In addition, the separate sealing member is attached to the sensor casing or the touch panel by bolt fastening or adhesive bonding that poses a risk of not being able to perform the intended sealing function due to insufficient bolt fastening or adhesive bonding, which makes it more difficult to control and achieve sufficient reliability.